Chemical curing in alkyd paints: An evaluation via FT-IR and NMR spectroscopies

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2014-01, Vol.118, p.520-525
• Main Authors: Bartolozzi, G., Marchiafava, V., Mirabello, V., Peruzzini, M., Picollo, M.
• Format: Article
• Language: English
• Subjects: 13C NMR; 1H NMR; Artists’ alkyd paints; Chemical curing; FT-IR
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2013.09.017

[Display omitted] •We studied the behaviour of one of the most widely used alkyd paint.•We wanted to determine the reaching of the chemical curing of the paint layer.•We monitored the decrease of double bonds in the chloroform extract of the paint.•1H NMR, 13C NMR and FT-IR were employed.•Allyl, diallyl and vinyl protons and carbons were used as markers. A study aimed at determining the time necessary for an alkyd paint to attain chemical curing is presented. In particular, the object of our investigation was an oil paint made by Winsor & Newton, namely French ultramarine (PB29) in the Griffin Alkyd “fast drying oil colour” series. Using this paint, we prepared several mock-ups on glass. These were left in the laboratory at room temperature in a piece of furniture with glass doors for a total of 70days. Samples were taken at different times, and the changes in their composition were monitored by means of FT-IR and multinuclear NMR spectroscopic analyses. Since the cross-linking reactions involved in the formation of the pictorial film mainly affect the amount of carbon–carbon double bonds, we monitored the decrease in allyl, diallyl and vinyl protons and carbons. The data obtained from the use of both techniques led us to conclude that, in our particular experimental conditions, the chemical curing of the paint layer is reached within the first 70days, thus establishing the beginning of the ageing phenomena.